Japan has introduced public participation into road planning processes in recent years. This paper firstly describes the Japanese institutional system of public participation in infrastructure planning; then it focuses on the institutionalization of participatory road planning procedure and road planning framework. Taking Yokohama Northwest Line for an example, it explains the planning procedure and public participation techniques in detail and analyzes the special advanced characteristics of the procedure. Finally, it suggests that China could learn the following experience from Japan: the institutionalization of participatory planning procedure, detailed division of road planning stages, setup of third-party organization, full publicity of information, and adoption of public suggestion, and implementation of multiple involvement techniques.